Protecting high-voltage transformers.



M. G. TROY.

PROTECTING HIGH VOLTAGE TRANSFORMERS.

APPLICATION FILED NOV.14,190B.

Patented July 28, 1914,

ZAJYEMTQR .1 UN TED STATES PATENT curios.

To all whom it may concern MATTHEW 0. rear,

rno'rnc'rme HIGH-venues rnansronmnns.

, Specification of Letters Yatent.

Patented July 28, 19.1

I Be it known-that I, MATTHEW O. TROY, a

citizen of the United States, residing at 10. I ne potential to those of a higher or lower Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements. in Protecting I-Iigh-Voltage Transformers, of wh ch the following is a specification.

; Th1s invent on relatestostationary electric transformers for converting currents of voltage as maybe desired;

-' In opera-ting step-down; transformers onhigh tension'transmissi'on lines the winding which may'come over is exposed to. great danger of injury by reason of surges of abnormally high potential the-line, arising from atmospheric lightning,"ac'cidental grounds,

-' improper manipulation of switches',-or what 'not. The end turns of the winding are those which sufier most, being frequently potential can distribute itself overthe entire short-circuited and burnedout before the coil. My invention aims to prevent'this trouble byplacing a small auxiliary transformer in I series with the main transformer and be-.

i tween it and the line to act as a buiier, so to speak, and take theconcen'tration' of potential which develops the end turns.

damage,'if any,- isthus confinedito the mixhected in serieswith t The iliary transformer which c'aribe 'readily r eplaced or repaired. This smalltransformer.

",may embody" special protective features, if" 35.

desired; It has its plrlmary winding cone primary of the maintransformer and 1ts secondary in series with .the secondary of the main transformer. so

long as it remains in commission, it performs part of the useful work of'transformatio'n, but, if, for: any reason, its turns become short circuited ei ther on primary or secondary it can remam in service without changingfthe ratio of transformation of the system, the main transformer being then operated at a higher density, as if it were connected directly to the line.

The efficiency of he auxlliary transformer is of no great'importance because of its small capacity. .It can, therefore, be designedto give the maximum amount of protection irrespective of eilicien'cy. It-can, forinstance,

be wound for higher reactance, therebyperforming the functions of reactive coils. Or,

it can have an edgewise winding of bare to cause an arcing over of current from turn,

to turn, I thereby quickly distributing the I strain. Or the turns can be spaced apart with air insulation; or immersed in oil; or

' taps-can be brought out from the turns and. spark gaps arranged between said taps, so as, to dissipate the potential when it'tends to. pile up on the end turns, and reduce the strain to a safe limit before it reaches the main transformer.

o SCHENEGTADY, NEW YORK, ess euoa r0 swam emerges. COMPANY, A CORPORATION Q1 NEW '2' In the accompanying drawing, Figure Ilia I a diagram illustrating my invention; Fig. 2

is a sectional elevation of an auxiliary transformer; Fig. 3 shows a portion of a transformer embodying the invention; Fig.

4 isa "diagram showing a further modifies.-

tion {and Fig. 5 shows another modification.

-Referring first to Fig. 1 the primary winding 1 of the main transformer is in series with the primary windings 1 of the auxiliary transformers which are located at 7 each endof the main transformer between it and the line w. The secondary winding 2 of the main transformer is, also-inseries with the secondaries Q of the auxiliaries, which;

are interposed between the main winding and the load circuit-y.

The construction of an auxiliary {ma vary'considerably. .Thus in Fig. 2- the'pri mary 3 is "an edgeWise-wound strip of bare copper, with interposed insulation 4, such as "micar The exposed edges of thefwindi-ng permit an arcing or fiashingofabnormal currents over the mica from turn to turn of the copper, until a safe distributionof the dangerous potentialhas been reached.

If desired, the mica may be omitted, and

air insulation alone depended on, or such a coil may be immersed in an oil tank 5', as

shown in Fig. Or, both the windings of the auxiliary transformer may be provided with regularly arranged taps 6- having spark-gaps 7 connected between adjacent taps, so that the excess of potential may jump the gaps andbe dissipated. The spark-gaps will extinguishany dynamic are which may attempt to follow of high potential.

the discharge I i f 9.?! Fig. 5 shows one magnetic circuit for-the: ,main] and auxiliary transformers, the core. 8 being common to both sets of wmdingll the invention cen be earned out by other 1-1562 2 2' with magnetic bridges 9 to, Ind a small auxiliary transformer permit-'1 "nentlyUincluded in each line connection in lite series between the line and .the correspond transformer tenninalandadapted to the concentration .of potential which dey'el'ops-in-the endturns. r

2. In combination, line conductors carry- 'ing electric current, a main transformer connected thereto, and a small auxlliarytransr former permanently connected to themain tra'nsformerat each end thereof between v1t and the cor-responding line conductor and ado ted to take'the concentration-of potential which develops in the. end turns. 3. In combination, line conductors carrying electric current, a main transformer con-- nected thereto, a small auxiliary transformer permanently connected to the main trans- .formerat each end thereof between it and the corresponding-line conductor and ada' t 'ed to take the concentration of potential which develops in'the endturns, and a common magnetic circuit for the momand auxiliary' transformers.

In witness whereof, I' have hereunto set my hand this 12th day of November,.1908. MATTHEW O. TROY.

Witnesses: 1

BEN AMI B. HULL, HELEN Onronn.

Copies 0! this patent my obtained for, five cents'eech, by eddressing the Commissioner or Patentn. I Washington, D. 03'] 

